Harvester makes crush rib sabots which may be easier to load.
There's .45 Powerbelts which are easier to load because they have a narrower plastic skirt.
Some folks that have tight bores use bore paste to polish the bore which helps to make loading sabots easier. Shooting plastic doesn't put much wear or help to break-in the bore very much. Whereas 50 or 100 strokes with bore paste can help to break-in the bore.
And then there's also using a mallet and a starter with a special tip to gently tap the bullets into the bore without damaging the pointed tip of the bullet. A lot of traditional shooters use a mallet to help with loading tight fitting patched round balls. Especially competition shooters who like really tight PRB's for better accuracy.